Old Caliber Ballistics

[3212]

Here's one for you ballistics experts.I have taken 16 deer with a 30-30 using 170 grain bullets and 3031 powder (basic factory load).I now have a 50 caliber flintlock with a 24 inch barrel.My best accuracy is with a roundball weighing I believe 170 grains and 70 grains of 2f powder.I would like to know if the flintlock equals the 30-30 in the energy department.

[Scorpion8]

Depends on the velocities. If they are comparable, then a 170gr projectile moving at the same speed from two different rifles will carry the same kinetic energy. It cares not what the projectile "is". For that you have to get into Taylor Knockdown Formulas, etc....

[3212]

I checked some charts,heres what I came up with.The .50 caliber with a 175 grain round ball in front of 70 grains of 2f has a muzzle velocity of 1700 fps.The factory 170 grain 30-30 has a muzzle velocity of 2200 fps.With the 24 inch barrel my velocity may be even lower.This confirms my decision to keep shots to less than 75 yds.My longest kill shot with the 30-30 was 150 yds.

[Scorpion8]

The formula for kinetic energy in generic terms is KE = 1/2 * (mass) * (velocity)^2, or 1/2 times the mass times the velocity squared. Reduced with all the proper conversion factors, it is KineticEnergy = .5 * weight * velocity^2 / 7000 / 32.175

Here's a good website: Bullet Kinetic Energy Calculator

So as it works out, your .30-30 has a KE at the muzzle of 1826ft-lbs, and your smokepole has a KE at the muzzle of 1122 ft-lbs. That being said, the roundball also has a "large slow moving punch" factor that makes it a good game-getter.

[Hunting Man]

Normally 50 cal round balls are 177 gr for .490. I wouldn't want to be hit with either a 50 cal or a 30-30, however, the two are so different that trying to compare them is apples and oranges. I prefer to load up the 50 round ball load to 90 gr of 3f. I shoot 100 gr of black horn in the in-lines for comparison. I do shoot 2f in the 54 cal at 110 gr.

[3212]

The flintlock was an impulse buy at a household auction.I didn't realize that a slow twist in a short barrel would limit my powder load.I think I'm getting unburned powder if I go higher and also the accuracy goes to pot.It has a 1 in 66 twist.

[Hunting Man]

The old test was, wait till you have snow on the ground and increase your charge grains until you see some unburned powder in the snow. 90 grains is plenty. The short barrel will cause you to lose some velosity due to potentially reduced loads and I wonder just how much bullet stability you are really getting out of the slow twist and the short barrel?? I'm not sure whether to suggest a 495 ball and a thin .010 patch or a 490 ball with a thick .017 patch to give you the best rifleing contact. Maybe others have a good suggestion, but I'd try both.

[3212]

Another thought.Thinking of the old 45/70.Would this load be a 50/70 and how close would the ballistics be for these two?